US2025128418A1PendingUtilityA1
In-situ robot material-reducing processing method and system for hydraulic turbine top cover
Assignee: CHINA YANGTZE POWER CO LTDPriority: Oct 19, 2023Filed: Sep 21, 2024Published: Apr 24, 2025
Est. expiryOct 19, 2043(~17.2 yrs left)· nominal 20-yr term from priority
Inventors:Hui LiuFangyu PengYichuan RanTao WuLin ZhouZaiming GengMing MaJian DengXiaolong YangJingling ZhouXiaoping ZhangHuren Zhou
B25J 9/1653B25J 9/1679B25J 19/023Y02E10/20B23C 3/00B25J 19/04B25J 19/02B25J 11/005B25J 9/1602
60
PatentIndex Score
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Claims
Abstract
An in-situ robot material-reducing processing method and system for a hydraulic turbine top cover are provided. The method includes: S1, obtaining frequency response data of an end of a cutter controlled by a robot by performing an impact hammer test; S2, obtaining a modal parameter of the end of the cutter controlled by the robot by using a modal analysis software; S3, obtaining a damping matrix [C] and a stiffness matrix [K] by using a free vibration equation of a damped system; S4, establishing a dynamic model of a three-degree-of-freedom robot processing system; S5, obtaining a milling force coefficient of the cutter by performing a calibration experiment; S6, solving a dynamic equation; S7, drawing a lobe diagram of flutter stability of a milling process performed by the robot; and S8, obtaining stable milling process parameters according to the lobe diagram of flutter stability.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . An in-situ robot material-reducing processing method for a hydraulic turbine top cover, the in-situ robot material-reducing processing method comprising the following steps:
S 1 , obtaining frequency response data of an end of a cutter controlled by a robot by performing an impact hammer test; S 2 , obtaining a modal parameter of the end of the cutter controlled by the robot by using a modal analysis software; S 3 , obtaining a damping matrix [C] and a stiffness matrix [K] by using a free vibration equation of a damped system; S 4 , establishing a dynamic model of a three-degree-of-freedom robot processing system; S 5 , obtaining a milling force coefficient of the cutter by performing a calibration experiment; S 6 , solving a dynamic equation; S 7 , drawing a lobe diagram of flutter stability of a milling process performed by the robot; and S 8 , obtaining stable milling process parameters according to the lobe diagram of flutter stability.
2 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 1 , wherein in the step S 1 , when the impact hammer test is carried out, an acceleration sensor is placed at an end of a milling electric spindle facing towards the cutter, and the end of the cutter is hammered with a hammer, the acceleration sensor is configured to collect the frequency response data, and a vibration acquisition platform is configured to obtain the frequency response data from the acceleration sensor.
3 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 1 , wherein in the step S 2 , the frequency response data are analyzed by the modal analysis software to obtain a frequency response function, and the modal parameter is obtained by solving the frequency response function, wherein the modal parameter comprises a modal mass matrix [M].
4 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 1 , wherein in the step S 4 , the dynamic model of three-degree-of-freedom robot processing system comprises a dynamic equation of a parameter K x and a parameter C x established on an X axis, a dynamic equation of a parameter K y and a parameter C y established on a Y axis, and a dynamic equation of a parameter K z and a parameter C z established on a Z axis.
5 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 1 , wherein in the step S 5 , a milling force coefficient matrix [K c ] is obtained by performing the calibration experiment.
6 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 1 , wherein in the step S 6 , the dynamic equation is as follows:
[
M
]
[
x
(
t
)
¨
y
(
t
)
¨
z
(
t
)
¨
]
+
[
C
]
[
x
(
t
)
.
y
(
t
)
.
z
(
t
)
.
]
+
[
K
]
[
x
(
t
)
y
(
t
)
z
(
t
)
]
=
[
K
c
]
[
x
(
t
)
-
x
(
t
-
T
)
y
(
t
)
-
y
(
t
-
T
)
-
(
z
(
t
)
-
z
(
t
-
T
)
)
]
,
wherein [M], [C] and [K] respectively represent a modal mass matrix, the damping matrix and the stiffness matrix of the end of the cutter controlled by the robot; [K c ] represents a milling force coefficient matrix; t and T respectively represent a current time and a cutter tooth period; x(t)−x(t−T), y(t)−y(t−T) and z(t)−z(t−T) respectively represent dynamic cutting thicknesses generated in X, Y and Z directions; x(t), y(t) and z(t) respectively represent dynamic displacements of the end of the cutter in the X, Y and Z directions; {dot over (x)}(t), {dot over (y)}(t) and ż(t) respectively represent first derivatives of x(t), y(t) and z(t); and {umlaut over (x)}(t), ÿ(t) and {umlaut over (z)}(t) respectively represent second derivatives of x(t), y(t) and z(t).
7 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 1 , wherein in the step S 7 , the dynamic equation is solved by a numerical integration method to obtain a result, and the lobe diagram of flutter stability of the milling process performed by the robot is drawn according to the result.
8 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 1 , wherein in the step S 8 , after the lobe diagram of flutter stability is obtained, stable milling process parameters are determined according to the lobe diagram of flutter stability, and process parameters below a stable boundary of the lobe diagram of flutter stability are parameters in which no flutter is generated during the milling process, and the stable milling process parameters comprise a rotational speed of a milling electric spindle and a milling depth of the cutter.
9 . An in-situ robot material-reducing processing system for a hydraulic turbine top cover, wherein the in-situ robot material-reducing processing system is configured to perform the in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 1 , and the in-situ robot material-reducing processing system comprises the robot and a milling electric spindle, a free end of the robot is provided with a six-axis force sensor, the milling electric spindle is installed on the six-axis force sensor, an fixed end of the robot is installed on a base, and an output shaft of the milling electric spindle is configured for installing the cutter for milling.
10 . The in-situ robot material-reducing processing system as claimed in claim 9 , wherein a vision device is installed on a side of the milling electric spindle.
11 . An in-situ robot material-reducing processing method for a hydraulic turbine top cover, the in-situ robot material-reducing processing method comprising the following steps:
S 1 , obtaining frequency response data of an end of a cutter controlled by a robot by performing an impact hammer test; S 2 , obtaining a modal parameter of the end of the cutter controlled by the robot by using a modal analysis software according to the frequency response data; S 3 , obtaining a damping matrix [C] and a stiffness matrix [K] by using a free vibration equation of a damped system; S 4 , establishing a dynamic model of a three-degree-of-freedom robot processing system; S 5 , obtaining a milling force coefficient matrix [K c ] of the cutter by performing a calibration experiment according to the damping matrix [C], the stiffness matrix [K], and a modal mass matrix [M]; S 6 , solving a dynamic equation by a numerical integration method to obtain a result; S 7 , drawing a lobe diagram of flutter stability of a milling process performed by the robot according to the result; S 8 , obtaining stable milling process parameters according to the lobe diagram of flutter stability; and S 9 , performing, by the robot, the milling process on the hydraulic turbine top cover based on the stable milling process parameters.
12 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 11 , wherein in the step S 1 , when the impact hammer test is carried out, an acceleration sensor is placed at an end of a milling electric spindle facing towards the cutter, and the end of the cutter is hammered with a hammer, the acceleration sensor is configured to collect the frequency response data, and a vibration acquisition platform is configured to obtain the frequency response data from the acceleration sensor.
13 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 12 , wherein in the step S 2 , the frequency response data are analyzed by the modal analysis software to obtain a frequency response function, and the modal parameter is obtained by solving the frequency response function, wherein the modal parameter comprises the modal mass matrix [M].
14 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 13 , wherein in the step S 4 , the dynamic model of three-degree-of-freedom robot processing system comprises a dynamic equation of a parameter K x and a parameter C x established on an X axis, a dynamic equation of a parameter K y and a parameter C y established on a Y axis, and a dynamic equation of a parameter K z and a parameter C z established on a Z axis.
15 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 14 , wherein in the step S 6 , the dynamic equation is as follows:
[
M
]
[
x
(
t
)
¨
y
(
t
)
¨
z
(
t
)
¨
]
+
[
C
]
[
x
(
t
)
.
y
(
t
)
.
z
(
t
)
.
]
+
[
K
]
[
x
(
t
)
y
(
t
)
z
(
t
)
]
=
[
K
c
]
[
x
(
t
)
-
x
(
t
-
T
)
y
(
t
)
-
y
(
t
-
T
)
-
(
z
(
t
)
-
z
(
t
-
T
)
)
]
,
wherein [M], [C] and [K] respectively represent the modal mass matrix, the damping matrix and the stiffness matrix of the end of the cutter controlled by the robot; [K c ] represents the milling force coefficient matrix; t and T respectively represent a current time and a cutter tooth period; x(t)−x(t−T), y(t)−y(t−T) and z(t)−z(t−T) respectively represent dynamic cutting thicknesses generated in X, Y and Z directions; x(t), y(t) and z(t) respectively represent dynamic displacements of the end of the cutter in the X, Y and Z directions; {dot over (x)}(t), {dot over (y)}(t) and ż(t) respectively represent first derivatives of x(t), y(t) and z(t); and {umlaut over (x)}(t), ÿ(t) and {umlaut over (z)}(t) respectively represent second derivatives of x(t), y(t) and z(t).
16 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 15 , wherein in the step S 8 , after the lobe diagram of flutter stability is obtained, stable milling process parameters are determined according to the lobe diagram of flutter stability, and process parameters below a stable boundary of the lobe diagram of flutter stability are parameters in which no flutter is generated during the milling process, and the stable milling process parameters comprise a rotational speed of a milling electric spindle and a milling depth of the cutter.
17 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 11 , wherein the in-situ robot material-reducing processing method is performed by an in-situ robot material-reducing processing system comprising the robot and a milling electric spindle, a free end of the robot is provided with a six-axis force sensor, the milling electric spindle is installed on the six-axis force sensor, an fixed end of the robot is installed on a base, and an output shaft of the milling electric spindle is configured for installing the cutter for milling.
18 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 17 , wherein a vision device is installed on a side of the milling electric spindle.
19 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 17 , wherein the six-axis force sensor is configured to collect a milling force in the milling process, and analyze the milling force to determine whether the cutter is seriously worn.
20 . The in-situ robot material-reducing processing method for a hydraulic turbine top cover as claimed in claim 18 , wherein the vision device is configured to measure an area to be machined of a hydraulic turbine top cover, and generate a milling trajectory and a machining program, and send the milling trajectory and the machining program to the robot, and the robot is configured to perform the milling process according to the milling trajectory.Join the waitlist — get patent alerts
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